Known floor cleaning machines use rotating brushes to scrub or polish a floor, mounted on a wheeled frame which is pedestrian controlled or in larger models is ridden on by the operator. Sufficient pressure is usually put on the brushes by the weight of the brush heads and motor assemblies in combination with the weight of the water tanks, though in larger models, hydraulic actuators are used, particularly on the ride-on machines. However, as brushes wear down the cleaning pressure decreases and hence the cleaning power is less satisfactory.
More recent pedestrian machines have tried to compensate for this by incorporating small springs into the brush heads so as to take up the wear in the brushes. These however have been found to be unacceptably unreliable in many circumstances because these springs have a tendency to lock and cause the driving motors to cut-out. In any case, in known machines, the maximum pressure is limited and there is no way of adjusting the pressure to be applied by the brushes. Pressures of up to 200 lbs. pressure can be achieved with the pedestrian machines but this is not adequate for heavy duty cleaning on very contaminated floors and is too high a pressure for normal maintenance cleaning. If the brush pressure is high then the brushes wear down very quickly. The sort of brushes used in this equipment are very expensive and excessive wear is unacceptable. In any case, excessive prolonged brush pressure may damage certain floor surfaces. On the other hand, if the brush pressure is too light then the cleaning machine will not be effective on heavily soiled floors.
Known machines make no allowance for uneven ground and tend to malfunction unless the floor is flat. Also, known machines are difficult and heavy to operate and manoeuvre and this makes them difficult, for example, for women to use.
It is an object of the present invention to provide a brush pressure system which does not have these disadvantages.